Mastering Vasopressors – Part 3
Reading Shock Like a Flight Medic: Warm vs. Cold Shock
"The monitor tells you what has happened. The patient tells you what's about to happen."
Walk into any emergency department, ICU, or helicopter.
Watch an experienced critical care clinician evaluate a patient.
You'll notice something interesting.
They don't immediately stare at the monitor.
They look at the patient.
Their hands.
Their skin.
Their breathing.
Their pulse.
Their mental status.
Within seconds...
They're already forming a differential diagnosis.
Long before the blood pressure cycles.
Long before the lactate comes back.
Long before the physician gives a diagnosis.
Great critical care clinicians learn to recognize physiology.
Not just numbers.
The Monitor Is Always Late
One of the biggest misconceptions in EMS is believing hypotension is the first sign of shock.
It isn't.
Hypotension is often one of the last signs.
By the time blood pressure finally falls...
The body has usually exhausted many of its compensatory mechanisms.
Think about trauma.
A healthy adult can lose a tremendous amount of blood before becoming hypotensive.
Why?
Because the body fights back.
Heart rate increases.
Blood vessels constrict.
Blood is redirected away from the skin, kidneys, and GI tract toward the brain and heart.
The monitor still looks "okay."
The patient isn't.
That's why elite clinicians don't wait for hypotension.
They recognize compensation before it fails.
Warm Shock vs. Cold Shock
Almost every patient in shock can initially be placed into one of two broad categories.
Warm.
Or cold.
It's one of the fastest bedside assessments you'll ever make.
Warm Shock
Warm shock usually means the problem is vascular tone.
The pump may still be working reasonably well.
The pipes have simply become too large.
Think:
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Septic shock
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Neurogenic shock
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Early distributive shock
-
Medication-induced vasodilation
What You See
Warm skin.
Bounding pulses.
Wide pulse pressure.
Flushed appearance.
Good capillary refill—at least early.
Despite looking warm...
The blood pressure may be terrible.
That's because the arteries have lost their ability to constrict.
Blood is flowing...
But pressure is disappearing.
Cold Shock
Cold shock usually means one of two things.
The pump isn't moving blood effectively.
Or...
There isn't enough blood to move.
Examples include:
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Cardiogenic shock
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Hemorrhagic shock
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Severe hypovolemia
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Late septic shock
What You See
Cold extremities.
Delayed capillary refill.
Weak peripheral pulses.
Cool, clammy skin.
Narrow pulse pressure.
The body is desperately trying to preserve blood flow to the heart and brain.
Everything else gets sacrificed.
Pulse Pressure: The Forgotten Vital Sign
Most providers look at blood pressure.
Few look at pulse pressure.
That needs to change.
Pulse pressure is simply:
Systolic Blood Pressure − Diastolic Blood Pressure
Example:
120/80
Pulse pressure = 40
Easy.
Now let's see why it matters.
Wide Pulse Pressure
Think:
Warm shock.
Sepsis.
Loss of vascular tone.
Blood runs into dilated arteries during systole...
But because those arteries are relaxed, diastolic pressure falls dramatically.
Example:
104/42
The MAP is concerning.
But the pulse pressure is huge.
That should immediately make you think distributive shock.
Narrow Pulse Pressure
Now imagine:
82/74
Very different.
The systolic pressure can't rise because stroke volume is poor.
The body clamps down on the arteries to preserve perfusion.
Result?
Tiny pulse pressure.
Think:
Cardiogenic shock.
Tamponade.
Massive hemorrhage.
Massive pulmonary embolism.
Cold shock.
Skin Never Lies
One of the most overlooked assessments in EMS is skin temperature.
Touch your patient's hands.
Touch their forearms.
Feel their knees.
Compare both sides.
Warm extremities often suggest distributive physiology.
Cold hands usually suggest poor cardiac output or severe vasoconstriction.
Your hands can diagnose physiology before the monitor does.
Capillary Refill
Remember learning capillary refill in EMT school?
Most people stop thinking about it.
Don't.
Delayed capillary refill is one of the earliest signs of poor peripheral perfusion.
Press the fingertip.
Release.
Watch.
Normal:
Less than two seconds.
Delayed?
Ask yourself why.
Poor cardiac output?
Hypovolemia?
Massive vasoconstriction?
The answer matters.
Mental Status
Never underestimate the brain.
Confusion.
Restlessness.
Agitation.
Sleepiness.
These are often early signs of inadequate cerebral perfusion.
A patient doesn't suddenly become altered.
Their brain has been underperfused for a while.
Listen to what the patient is telling you.
Sometimes confusion is simply another vital sign.
ETCO₂: The Secret Shock Monitor
If I could add one more vital sign to every EMS truck...
It would be continuous waveform capnography.
Not because of intubation.
Because of perfusion.
ETCO₂ reflects three things:
Ventilation.
Perfusion.
Metabolism.
If cardiac output drops...
Less CO₂ reaches the lungs.
ETCO₂ falls.
Sometimes it falls before blood pressure changes.
A patient whose ETCO₂ drops from 36 to 24 without a ventilatory change is telling you something.
Listen.
The Neck Never Lies Either
Take a moment to look at the jugular veins.
Flat neck veins?
Think:
Hypovolemia.
Hemorrhage.
Dehydration.
Bulging neck veins?
Think:
Tamponade.
Tension pneumothorax.
Right ventricular failure.
Massive pulmonary embolism.
One glance can completely change your differential.
The Hands Tell the Story
Experienced flight clinicians often shake a patient's hand.
Not to be polite.
To assess perfusion.
Warm?
Dry?
Cold?
Clammy?
Sweaty?
Weak pulse?
Bounding pulse?
You'd be amazed how much physiology is sitting in someone's fingertips.
The Patient Who "Looks Sick"
Have you ever walked into a room and thought...
"I don't like this patient."
But you couldn't explain why?
That's experience recognizing subtle physiology.
Pale skin.
Quiet voice.
Delayed responses.
Weak eye contact.
Slight diaphoresis.
Minimal movement.
Those clues matter.
Never ignore your instincts.
Often your subconscious recognizes shock before your conscious brain does.
Ultrasound Changes Everything
Point-of-care ultrasound has become one of the most valuable tools in critical care transport.
Even a focused exam can answer important questions.
Is the left ventricle barely squeezing?
Think cardiogenic shock.
Is the IVC collapsed?
Think hypovolemia.
Is the right ventricle massively enlarged?
Think pulmonary embolism.
Is there a pericardial effusion?
Think tamponade.
Ultrasound doesn't replace your assessment.
It confirms it.
Reading Shock in 30 Seconds
Imagine you walk into a room.
The patient is:
Cold hands.
Weak radial pulse.
Narrow pulse pressure.
Delayed capillary refill.
ETCO₂ of 22.
Flat neck veins.
What's your first thought?
Probably hypovolemia.
Now another patient.
Warm hands.
Bounding pulses.
Wide pulse pressure.
ETCO₂ 32.
Flushed skin.
Febrile.
Immediately you're thinking distributive shock.
That's physiology.
Not protocol.
The Biggest EMS Mistake
The biggest mistake isn't choosing the wrong pressor.
It's choosing one before identifying the type of shock.
Levophed doesn't fix tamponade.
Dobutamine doesn't fix hemorrhage.
Fluids don't fix cardiogenic pulmonary edema.
Blood doesn't fix neurogenic shock.
The treatment only makes sense after the diagnosis.
Flight Medic Pearls
✔ Your hands are diagnostic tools.
✔ Pulse pressure tells a story.
✔ ETCO₂ is a perfusion monitor.
✔ Skin temperature often changes before blood pressure.
✔ Neck veins can reveal obstructive shock in seconds.
✔ Treat the patient—not the monitor.
✔ Compensation is still shock.
Don't wait for hypotension to believe your patient.
The Flight Medic Scan
Before you ever touch the monitor, train yourself to scan for these clues:
Look
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Skin color
-
Work of breathing
-
Mental status
-
Neck veins
-
Overall appearance
Touch
-
Hand temperature
-
Pulse quality
-
Skin moisture
-
Capillary refill
Listen
-
Speech
-
Breath sounds
-
One-word answers?
-
Confusion?
Think
-
Is the pump failing?
-
Are the pipes too relaxed?
-
Is the tank empty?
-
Is something obstructing circulation?
This entire assessment can happen in less than 30 seconds.
And it will often tell you more than the first blood pressure cuff.
Bottom Line
The best critical care clinicians don't diagnose shock by staring at a monitor.
They diagnose it by recognizing physiology.
Warm or cold.
Bounding or weak.
Wide pulse pressure or narrow.
Warm hands or cold fingertips.
Bounding neck veins or flat veins.
The patient is constantly giving you clues.
Your job is to notice them.
When you stop asking,
"What's the blood pressure?"
And start asking,
"What type of shock am I looking at?"
You'll begin practicing critical care medicine at an entirely different level.
Because the monitor tells you what has happened.
But the patient tells you what is about to happen.
Coming Up Next
Mastering Vasopressors – Part 4
When Pressors Fail: Identifying the Hidden Cause of Refractory Hypotension
We'll tackle the patients who don't respond the way they "should." We'll explore why escalating norepinephrine isn't always the answer, how to recognize occult hypovolemia, adrenal insufficiency, obstructive shock, right ventricular failure, acidosis, calcium depletion, and the physiologic traps that keep patients hypotensive despite multiple vasopressors. Because sometimes the problem isn't that you need more pressor—the problem is that you're treating the wrong disease.